import { describe, it, expect, beforeEach } from "vitest";
import { part, emit, initialValue, listen, wireLabel } from "../src/shared/helpers";

describe("shared helpers", () => {
  beforeEach(() => { document.body.replaceChildren(); });

  it("part() finds child by data-part attribute", () => {
    const host = document.createElement("div");
    const child = document.createElement("input");
    child.dataset.part = "control";
    host.appendChild(child);
    expect(part(host, "control")).toBe(child);
    expect(part(host, "missing")).toBeNull();
  });

  it("emit() dispatches a bubbling petty-prefixed event", () => {
    const el = document.createElement("div");
    document.body.appendChild(el);
    let received: { value: unknown } | null = null;
    document.body.addEventListener("petty-change", (e) => { received = (e as CustomEvent).detail; });
    emit(el, "change", { value: "test" });
    expect(received).toEqual({ value: "test" });
  });

  it("initialValue() reads default-value then value then empty", () => {
    const el = document.createElement("div");
    expect(initialValue(el)).toBe("");
    el.setAttribute("value", "v");
    expect(initialValue(el)).toBe("v");
    el.setAttribute("default-value", "dv");
    expect(initialValue(el)).toBe("dv");
  });

  it("listen() attaches and cleanup removes listeners", () => {
    const el = document.createElement("button");
    let count = 0;
    const handler = () => { count++; };
    const cleanup = listen(el, [["click", handler]]);
    el.click();
    expect(count).toBe(1);
    cleanup();
    el.click();
    expect(count).toBe(1);
  });

  it("listen() returns noop for null element", () => {
    const cleanup = listen(null, [["click", () => {}]]);
    expect(typeof cleanup).toBe("function");
    cleanup();
  });

  it("wireLabel() connects label htmlFor to control id", () => {
    const control = document.createElement("input");
    const label = document.createElement("label");
    wireLabel(control, label, "test");
    expect(control.id).toMatch(/^test-/);
    expect(label.htmlFor).toBe(control.id);
  });

  it("wireLabel() does nothing with null label", () => {
    const control = document.createElement("input");
    wireLabel(control, null, "test");
    expect(control.id).toBe("");
  });
});